The present invention relates to an armature, a method for manufacturing the armature, and a motor. The armature has a core and a wire, which is wound about and is easily detached from core teeth of the core.
There is a great demand for motors that can be easily recycled these days. Motors are compressed and crashed by a shredder to be recycled. An armature is one of components of a motor and has a core. The core is generally made of iron core sheets piled in layers. Therefore, when compressed by the shredder, the core is simply deformed. As a result, teeth of the core are twisted and the wire is not easily removed from the teeth. Thus, the core and the wire that need to be separated are not easily detached from each other.
Japanese Laid-Open Patent Publication 2000-152532 discloses an armature that permits a core and a wire to be easily separated. In the above publication, the core is formed by molding magnetic metal powder. In this case, since the core is highly brittle, or has low ductility, when compressed by a shredder, teeth are broken and each part of the core is crashed so that the wire and the core are easily separated from each other.
However, in the art disclosed in the above publication, a rotary shaft is directly press fitted in the core so that the core is secured to the rotary shaft. Since the core is highly brittle, the press fit allowance needs to be reduced to prevent the core from being broken. Thus, the core of the above publication is particularly not suitable for high-power motors.
Therefore, adhesive is generally applied between the core and the rotary shaft to firmly fix the core to the rotary shaft. However, applying adhesive complicates the procedure, which is not favored. Further, the adhesive is easily affected by temperature changes and the fixing force is reduced by temperature changes.
Accordingly, it is an objective of the present invention to provide an armature that permits a core to be firmly secured to a rotary shaft, a method for manufacturing the armature, and a motor that uses the armature.
To achieve the above objective, the present invention provides an armature, which includes a rotary shaft, a core, and a coupling member. The core is formed by using magnetic metal powder and has a tooth. A wire is wound about the tooth. The coupling member has ductility that is higher than the ductility of the core. The coupling member is located between the core and the rotary shaft. The rotary shaft is press fitted in the coupling member, and the coupling member is press fitted in the core.
The present invention may also be embodied in a method for manufacturing an armature. The method includes: preparing a rotary shaft; forming a core using magnetic metal powder, wherein the core has a tooth to which a wire is wound; press fitting a coupling member having ductility that is higher than the ductility of the core to the core; and press fitting the rotary shaft to the coupling member, which is press fitted to the core.
The present invention also provides a motor having an armature. The armature includes a rotary shaft, a core, and a coupling member. The core is formed by using magnetic metal powder and has a tooth. A wire is wound about the tooth. The coupling member has ductility that is higher than the ductility of the core. The coupling member is located between the core and the rotary shaft. The rotary shaft is press fitted to the coupling member, and the coupling member is press fitted to the core.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.